FXUS65 KBOI 222330
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
530 PM MDT Sat Aug 22 2026

.UPDATE...Updated aviation discussion.

&&

.KEY MESSAGES...
- Scattered showers and strong thunderstorms in south-central
  Idaho through this evening. Isolated showers and weaker
  thunderstorms elsewhere in western Idaho until sunset.
  Clearing in eastern Oregon.

- Gusty outflow winds up to 50 mph from thunderstorms in south-
  central Idaho through sunset.

- Dry and slightly cooler Sunday, then several degrees warmer
  again Monday with a chance of afternoon thunderstorms in
  southern areas.

&&

.SHORT TERM /Through Monday Night/...
Issued 213 PM MDT SAT AUG 22 2026
At 1 PM MDT scattered showers and thunderstorms were already 
underway in Owyhee and Twin Falls Counties, moving northeast.
These will increase in coverage the rest of the afternoon and
early evening, particularly in eastern Owyhee and Twin Falls 
Counties where monsoon moisture still exists. Meanwhile, a 
Pacific cold front has developed a band of light rain showers 
and isolated thunderstorms in Baker and Malheur Counties. The 
front and the showers/storms will move eastward into Idaho this 
afternoon and evening and help enhance the thunderstorms in 
south-central Idaho. Cooler and drier air will come in from the 
west overnight and Sunday, but a slight chance of afternoon 
thunderstorms will develop again in Twin Falls County Sunday 
afternoon. Monday looks several degrees warmer again as an 
upper trough exits east, replaced by a weak upper ridge over
Oregon. Mid-level moisture will again increase and lead to a 15
to 30 percent chance of afternoon and evening thunderstorms in 
southern areas, while northern areas stay dry with increasing 
clouds in the afternoon.

&&

.LONG TERM /Tuesday through Saturday/...
Issued 213 PM MDT SAT AUG 22 2026
Troughing off the shore of Washington and Oregon will keep most
monsoonal moisture east of our area. This will keep mostly dry 
conditions across the area, with a low chance (under 15%) of 
afternoon showers and thunderstorms across our far eastern 
zones. Otherwise, breezy conditions will set in with a slight 
cooling trend. Temperatures come Tuesday will be around 5-10 
degrees above normal, cooling to near normal come Saturday.

&&

.AVIATION /00Z Sunday through Monday/...
Issued 529 PM MDT SAT AUG 22 2026

VFR. Scattered showers and thunderstorms this afternoon. 
Coverage will continue this evening mainly in SW-Idaho. Thunder
capable of brief heavy rain, hail, and erratic outflows to 
40-50 kt. BLDU possible with outflows. High density altitude 
this afternoon due to heat. Surface winds outside of storms: 
Variable 5-15 kt, except SW 10-20 kt with gusts to 25-30 kt in
E-Oregon through 03z. Winds aloft at 10kft MSL: S-SW 10-25 kt.

KBOI...VFR. A 20% chance of thunderstorms this afternoon into
evening. Thunderstorms capable of brief heavy rain, hail, and 
outflows to 30-40 kt. BLDU possible in outflows. High density 
altitude this afternoon due to heat. Surface winds: NW-N 6-12 kt
this afternoon, becoming SE 5-15 kt tonight. 

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning until midnight MDT tonight for IDZ401>403-421-
     424-426.
OR...     Red Flag Warning until 8 PM PDT this evening for ORZ670>672.
&&

$$

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AVIATION.....CH
SHORT TERM...LC
LONG TERM....NF